Due to the problems of complex regulation, large mass, and poor adaptability, the traditional ship leak-plugging umbrella is often difficult to be effectively applied in the process of warship leak-plugging. In this paper, starting from the technical scheme and performance characteristics of naval leak plugging umbrella, a design of naval anti-umbrella plugging umbrella based on water-absorbing and expanding rubber material is proposed. Based on the good ductility and elasticity of the swollen rubber material after absorbing water, it achieves the anti-parachute coverage of the breach under the action of water pressure. Meanwhile, an axisymmetric non-linear finite element analysis model of the rubber plugging umbrella is established using ABAQUS to analyse the stress-strain state of the umbrella at different water depths. The results show that the new leak plugging umbrella has a reasonable design, high pressure strength and good sealing performance, which can significantly improve the ship's leak plugging capacity and has broad application value.
With the rapid development of wireless technology, indoor positioning using WiFi has become a hot spot in the current positioning field. At present, WiFi signals are ubiquitous, resulting in uneven AP deployment and redundancy, which affects positioning accuracy. In this paper, an AP selection algorithm based on information entropy and mutual information is proposed by analyzing the characteristics of AP signals to optimize the AP. Its positioning accuracy is significantly better than the other two AP selection algorithms.
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